The meal that's key to losing weight

WHEN it comes to losing weight there must be a thousand different theories out there.

But what if it was a simple as when you eat your food, instead of what you can and can't eat?

The time we eat has a big impact on our internal body clock, which can have a huge impact on our waistlines.

You may think your body clock, also known as the circadian rhythm, only affects your sleeping patterns, but the fact is there is a clock in every cell of your body.

Eating a big meal late at night is not the right thing for your metabolism - instead you should be having a big lunch.

Eating a substantial lunch, like this big healthy salad, is the key to weight loss. Picture: Claudia Baxter

"There is evidence coming through that having the majority of your calories earlier in the day seems to be more beneficial than having a heavier evening meal," nutritionist Helen Bond said.

"It's about shifting the bulk of your calorie intake more to the middle part of the day, rather than eating a big meal late at night, and going to bed on an empty stomach.

"But it's also important to be mindful of your overall calorie intake throughout the day.

"There is no point in having a very calorific meal at lunchtime and not compensating by eating less later on.

"If you have a more carbohydrate-calories-based meal at lunchtime then you are going to be burning those calories more efficiently in terms of insulin levels and your metabolism."

You should be tucking into a bigger lunch — and a smaller dinner. Picture: Claudia Baxter/AAP

But it's important not to forget about eating well for breakfast and dinner, Helen said.

"The old tradition is breakfast like a king, lunch like a prince and dinner like a pauper, and I think that very much rings true today," she said.

"Having a good breakfast refuels you after the overnight fast and provides you with energy to concentrate and improves your mood.

"For lunch time, if you are having a heavier meal, you have the afternoon to use all those calories.

"It means you are going to bed with not such a heavy stomach and your body can metabolise those calories more efficiently.

"Calories in, calories out still has a bearing on how much weight we gain or maintain, but also what is really important is the nutrient density of those calories.

"Not all calories are equal and if your diet is lacking in nutrition that's not going to be beneficial for your weight as well."

Some evidence suggests you use more energy to burn off a meal earlier in the day than you do at night.

And animal studies have found that eating at specific times can help reset the body's circadian rhythm.

Other research has suggested a big breakfast can help you lose weight and treat diabetes.

People with type 2 diabetes who followed a diet plan of a high-energy breakfast, followed by an average-sized lunch and small dinner not only lost weight but their body was able to manage their blood sugar levels better.

The Tel Aviv University study of 11 women and 18 men found that those on a diet of three meals a day including a big breakfast, called the Bdiet, lost an average of 5kg over three months.

And research from Sheffield Hallam University found that people who have a substantial breakfast eat less throughout the day.

Previous studies have suggested that people feel fuller for longer if they expect their food and drink to be filling.